We literally turned up the heat to make things more interesting. Using a hot-box with a brutal ambient temperature of 30 degrees Celsius, we took our quad CrossFire setup through its paces with a 1000 W 80 Plus Bronze certified power supply unit. You might assume we'd need a beefier power source, but our launch article measurements indicate that the total power consumption of these two graphics cards plus the benchmarking system should be about 1000 W. This PSU should be able to handle the load without any trouble.
A one-hour gaming loop with almost 100 percent load results in a measured power draw of 1100 W at the Chroma’s primary side. This means that our overall system draw stays well under 1000 W, proving that our previous measurements align almost exactly with what we see in practice.
Then again, we can also remember situations when a single AMD Radeon R9 295X2 managed to shut down a PSU (PCGH, 1200W Enermax Platimax), or even destroy it outright (Tom's Hardware, Corsair AX860i). In these cases, the power supplies should have had more than enough capacity to handle the hardware.
We used a be quiet! Power Zone 1000 W PSU for this experiment in our self-imposed 30-degree-Celsius hotbox. Amazingly, there are no failures to report. The reason for its stability is likely attributable to the better design of its PCIe power connectors. Its capacitors are better able to deal with the AMD Radeon graphics card’s peaks in power consumption.
Our previous attempt with the 1200 W Enermax Platimax and the AMD Radeon R9 295X2 showed us that the PSU did not shut down as many people assumed, but that the motherboard wasn't able to handle a brief decrease in voltage. The PSU’s under voltage protection (UVP) isn't even able to register this particular issue.
The video shows a panning shot of our benchmark setup with Chroma and power supply.
So what have we learned? Primarily that nothing beats precise measurements and a clean, well-thought-out primary side of a PSU. Prestigious certificates don't amount to much, because it's what’s inside is what counts. Finally, the AMD Radeon R9 295X2 isn’t as bad as its reputation might suggest, as long as it’s combined with the right PSU.
Relevant Links:Radeon R9 295X2 8 GB Review: Project Hydra Gets Liquid CoolingUpdate: Radeon R9 295X2 8 GB In CrossFire: Gaming At 4K